You see the "fatal flaw" in that scene isnt that Alia still had powers, it's the Zod didnt so quickly. From comic lore, Kryptonians are like solar batteries they absorb the energy from the sun and then store it. A battery doesnt immediately become powerless once it's not being charged. It has to be drained first.
Zod shouldnt have run out of powers the second the sun turned yellow again. he would still have all of that red solar energy stored in him. He'd have to use it all up first and then he'd be powerless. (You should mention that in your K-Site review..and credit me of course

)
So Alia having a burst of superspeed only minutes after the sun turned isnt all that unbelievable given what we know about the Kandorians. The scene really failed by having Zod's powers shut off like a light switch. The show has made that mistake in a few episodes with Clark as well. Their powers dont come and go the instant the sun hits them or goes away. Otherwise Clark would never have any powers when it was night time. (or atleast very diminished powers since moonlight is in effect reflected sunlight)
One of the times where the show really got this point right was in
Perry where they mentioned Clark had to burn off the energy overload from the solar flares before he returned to "normal."